Williamson's next film was also about high schoolers in peril. I Know What You Did Last Summer, based on a 1973 novel by Lois Duncan, had four friends accidentally running over a man, dumping the body, and going on with their lives, only to be punished one year later. After Columbia Studios advertised the film as "from the makers of Scream" against Miramax's wishes, Miramax released Scream 2, also written by Williamson, and filed a lawsuit against Columbia. Scream 2 would also be a hit and would spawn a third film, Scream 3, as the final installment of the Screamtrilogy. Williamson wrote another in this genre, The Faculty, characterized as "Invasion of the Body Snatchers meets The Breakfast Club."

Williamson is currently the writer and producer for "Scream 4" which is scheduled to begin shooting in June of 2010 and will hit theaters April 15th 2011.

Dawson's Creek premiered on The WB January 20, 1998, and was an immediate hit with its intended audience. Despite this (and his having told Entertainment Weekly that "I ain't never leaving Dawson's Creek"), Williamson left the show at the end of its second season to create a show for Miramax to air on ABC. The result, Wasteland, about twentysomethings in New York City was savaged by critics. The Hollywood Reporter said it was about "the most attractively vacuous, self-indulgent, and pretentious group ever assembled in prime-time." It aired only three episodes in October 1999 before ABC cancelled it. (Williamson would return to Dawson's Creek to write the two-part series finale in 2003.)

Williamson created a mid-season replacement for The WB network called Glory Days, set in a coastal community in Washington state, where very weird things were happening--shades of Twin Peaks, it seemed. It debuted as a mid-season replacement in January 2002; only ten episodes were produced.

Williamson wrote and produced this show for The CW. It was a coming-of-age drama about a troubled teen who moves with his mother and new stepfather to the gated community of Palm Springs where he uncovers some dark secrets. Hidden Palms was originally intended to be a midseason replacement set to air in March but Pussycat Dolls Present: The Search for the Next Doll aired in its timeslot instead. The Pilot eventually premeried on May 30, 2007. Eight episodes were ordered by the network but due to low ratings the series was cancelled. The final episode aired on July 4, 2007.